The present invention relates to subsurface well equipment and, more particularly, to a sand control method and apparatus.
It is well known to those engaged in the exploration of oil and gas that certain subterranean hydrocarbon-producing formations have sand commingled with the hydrocarbons. For various reasons, which are well-known in the art, it is not desirable to produce the commingled sand to the earth""s surface along with the hydrocarbons. As such, the industry developed sand-control completions that, in broad terms, include an upper and an optional lower, or sump, packer with various mechanisms disposed therebetween, including a closing sleeve and a sand screen. The upper packer, such as a seal bore retrievable packer, is initially connected to a service string, and the entire sand-control completion is lowered into the well on the service string until the sand screen is positioned adjacent the hydrocarbon-producing formation. If the well is cased, then the sand screen will be positioned adjacent perforations in the casing. A service tool in the service string is used to perform various functions and operations with regard to the sand-control completion, including washing down the well bore as the string is run into the well bore, setting the packers, displacing fluids in the annulus above the upper packer, squeezing fluids into the production annulus and into the formation (e.g., through the casing perforations), packing gravel into the annulus between the sand screen and the formation, circulating fluids into the production annulus, and reverse-circulating fluids out of the service tool and service string. After all necessary operations have been carried out, and the sand-control completion is ready to produce the hydrocarbons to the earth""s surface, the service string and tool are disconnected from the upper packer and removed from the well. A production tubing is then lowered into the well and connected to the upper packer, at which time production operations may commence. All of these functions and operations are known to those skilled in the art of sand-control and gravel pack completions.
It is also well known that it is not uncommon for a single well to have multiple producing zones, such as an upper zone and a lower zone. In this situation, the lower zone is typically completed in the manner discussed in the preceding paragraph. Next, instead of stabbing a production tubing into the upper seal bore packer (i.e., the one above the lower zone), the service string is used to run a second sand-control completion into the well and stabbed into the upper packer. This second sand-control completion is then used to complete the upper zone in the same manner as discussed above. It is desirable in some instances, however, to complete the multiple zones with a single run of the completion equipment.
In general, according to one embodiment, a string comprises a tubing, a sealing element coupled to the tubing, a sand control device positioned downstream of the sealing element, and a tool adapted to be run through the tubing to perform at least one of a gravel pack operation, a fracturing operation, a cleaning operation, and a stimulating operation.
Other features and embodiments will become apparent from the following description, from the drawings, and from the claims.